Rafael Martin

Dr. Rafael Martin

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Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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4 June 2018 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
RMRafael Martin
Rafael Martin
AGAlvaro Garcia-Martin
Alvaro Garcia-Martin
AHAlexander G. Hauptmann
Alexander G. Hauptmann
JMJose Martinez
Jose Martinez
This paper presents a multicamera system for vehicles detection and their corresponding mapping into the parking spots of a parking lot. Approaches from the state-of-the-art system, which work properly in controlled scenarios, have been validated using small amount of sequences and without more challenging realistic conditions (illumination changes and different weather conditions). On the other hand, most of them are not complete systems, but provide only parts of them, usually detectors. The proposed system has been designed for realistic scenarios considering different cases of occlusion, illumination changes, and different climatic conditions; a real scenario (the International Pittsburgh Airport parking lot) has been targeted with the condition that existing parking security cameras can be used, avoiding the deployment of new cameras or other sensors infrastructures. For design and validation, a new multicamera data set has been recorded. The system is based on existing object detectors (the results of two of them are shown) and different proposed postprocessing stages. The results clearly show that the proposed system works correctly in challenging scenarios including almost total occlusions, illumination changes, and different weather conditions.

11 December 2018 in Sensors
Verified
Journal Article
Open access
PDF file
RMRafael Martin
Rafael Martin
AGAlvaro Garcia-Martin
Alvaro Garcia-Martin
JMJose Martinez
Jose Martinez
JMJuan Carlos San Miguel
Juan Carlos San Miguel
Finding optimal parametrizations for people detectors is a complicated task due to the large number of parameters and the high variability of application scenarios. In this paper, we propose a framework to adapt and improve any detector automatically in multi-camera scenarios where people are observed from various viewpoints. By accurately transferring detector results between camera viewpoints and by self-correlating these transferred results, the best configuration (in this paper, the detection threshold) for each detector-viewpoint pair is identified online without requiring any additional manually-labeled ground truth apart from the offline training of the detection model. Such a configuration consists of establishing the confidence detection threshold present in every people detector, which is a critical parameter affecting detection performance. The experimental results demonstrate that the proposed framework improves the performance of four different state-of-the-art detectors (DPM , ACF, faster R-CNN, and YOLO9000) whose Optimal Fixed Thresholds (OFTs) have been determined and fixed during training time using standard datasets.


1 February 2014 in Electronics Letters
Verified
Journal Article
Open access
PDF file
RMRafael Martin
Rafael Martin
JMJose Martinez
Jose Martinez
A correlation study of a set of video object trackers evaluation metrics is presented. There are multiple metrics in the state‐of‐the‐art, and the main differences between them are based on the penalties that are attributed to the errors (false positives, false negatives, target loss etc.). After defining each one of the considered metrics, a correlation study is presented showing the redundancy between all the metrics. This reported study was performed using multiple tracking algorithms, and an extensive set of video sequences that attempt to cover many different situations.

31 October 2018 in Multimedia Tools and Applications
Verified
Journal Article
Closed access
PDF file
RMRafael Martin
Rafael Martin
AGAlvaro García-Martín
Alvaro García-Martín
JMJose Martinez
Jose Martinez